Cross-Correlative Least-Squares Reverse Time Migration — Theory and Field Applications

Abstract

We introduce a new practical least-squares reverse-time migration (LSRTM) scheme and derive a steepest descent method for optimal imaging by adapting reverse-time migration (RTM) and demigration (RTDM) as the migration and modelling operators to maximize the cross-correlation between simulated and acquired seismic data. Through real data experiments, we demonstrate that the proposed LSRTM provides high quality images with balanced amplitudes, improved focusing and enhanced resolution. The method is also capable of removing the free surface ghosts generated in towed streamer acquisition and filling holes in the imaged structures due to imperfect acquisition. Together with impedance perturbation technique, the proposed method is a useful tool for both seismic imaging and inversion.